(402d) Fixed Bed Modeling Revisited; Generalized Solutions for S-Shaped Isotherms

Both theoretical models and experiments that study the effects of the shape of the equilibrium isotherm on the fixed bed dynamics are limited to systems which obey rectangular (irreversible), linear and favourable equilibrium isotherms rather than unfavourable or more complicated equilibrium isotherms, such as S-shaped (Type IV or V). Furthermore, most modeling studies focus on the application of models on particular systems, hence, the derived conclusions are either system-specific or they are based on phenomenological models which exhibit no physical significance to the experimental setup. Moreover, the theoretical models are further restricted as they are solved under certain assumptions; mostly constant pattern and ideal plug flow. This paper presents results on rather unusual fixed bed dynamics, i.e. for systems that follow S-shaped isotherms, and fixed beds that operate in non-asymptotic and non-ideal flow conditions. The solutions are generalized by considering models that are based on classical dimensionless parameters, and the derived conclusions are applicable to any system that obeys the underlying assumptions.